Apparatus for separating liquids



Sept. 15, 1959 Filed Nov. 28, 1955 INVENTOR mm. AW.

A TTORNE APPARATUS non SEPARATING LIQUIDS Leslie Bristow, London, England, 'assignor of two-thirds to Henry Arthur John Silley and Douglas George Unthank, both of London, England Application November 28, 19-55, Serial 549335 Claims priority, application Great Britain-* November 30,1954

8 Claims. (CL 210-109 This invention is concerned with improvements in and relating to apparatus for separating liquidsof different specific gravities, such as oil and water, and has for an object to provide new apparatus. 7

According to the present invention there is provided apparatus for separating liquids of diiferent specific gravities comprising a closed container, an inlet to the contates PatentO tainer interior for liquids to be separated, two outlets from the container interior each for a different separated liquid constituent of the liquids to be separated, means within the container interior connecting the said inlet and the two outlets and providing a passage through which liquids in the container are caused to flow and change direction and thereby separate into two constituent liquids, a valve in one of the said'two outlets biased to oppose flow of the respective separated constituentliquid from the container interior, a valve in the otherof said two outlets actuated by a liquid-operated -motor, and means for applying to the said liquid-operated motorfor operation thereof liquid under pressure from the interior of the separator.

The said liquid-operatedmotor may comprise'a' piston working in a cylinder, the liquid underpressure supplied thereto causing movement of the piston toopenjthevalve. The piston may be of the double-acting type and'the liquid under pressure may be fed thereto alternatively to move the piston to open and close the valve; The said valve in the other of the said two outlets may be of the poppet type and biased to the closed position by the pressure of liquid in the interior of the container; I j

An embodiment of the invention comprising apparatus for separating oil and water will now be described, by way of example, with reference to the accompanying diagrammatic drawing which shows a longitudinal section through the separator with a part thereofbroken away to show details of the control apparatus.

The separator comprises a closed container of cylindrical shape formed from upper and lower cup-shaped parts 10 and 11 placed mouth to mouth and fastened together by bolts, etc., passing through co-operating flanges 12 and 13 respectively provided around the abutting circular edges of the parts. When the container is in its operating position the axis of the'cylinder is vertical,

the end of the lower cup-shaped part 11 being provided with feet 14 by which the container is mounted on the floor. Manholes (not shown) are provided in th'e's'ide walls of both parts to give access to the container interior for cleaning and inspection.

Threeconduits 15, 16 and 17 mounted in the container proximately equal-parts which are held together by bolts passing through flanges 20, the joint lying in substantially the same plane as that of the joint between the parts 10 and 11.

-In this embodiment the middle conduit 16 is about /3 the length of the innermost conduit 15 and is mounted around the lower end of the innermost conduit with its own lower end 21 fitting closely within a ring 22 fixed to the container floor to provide sealing engagement between .the conduit and the container floor. The outermost conduit 17. has its upper end fixed to the lower half of the innermost conduitlS, immediately below the flange 20 thereof, whilst its lower end, whichis of larger diam eterthan the said upper end, extends into the neighbourhood of the container floor.

A small perforated, annular baflie 23 is mounted in the part of the passage between the middle and outermost conduits, and a larger perforated, annular baffle 24 is arranged to extend into the upper part of the container in the part of the passage between the outermost conduit and the, container inner wall. A pipe 25 enables separated oil which collects in the upper part of the outermost conduit 17 to pass to the upper part of the separator.

Water contaminated with oil is introduced into the container through an inlet 26 formed by a pipe 27 projecting through the container ceiling, the inlet port to the container being arranged to direct the liquid circumferentially around the upper part of the container. A heating coil 28 is provided at the top of the tank and is heated by steam when necessary to keep the oil at the top of the tankin the fluidcondition. Air is released as necessary through a valve 29 at the top of the container.

All movement of liquid in the container is comparativelyslow-and turbulence is avoided as far as possible. The liquid passes downwards inthe part of the passage between the outermost conduit 17 and the container inner wall. through the perforations in the larger baffle 24, the baffle causing the liquid to flow downwards in a number of separate vertical streams. Near the container floor the liquid undergoes an abrupt change of direction and travels upwards in the part of the passage between the outermost and middle conduits 17 and 16 respectively. The liquid moves through the small baflie 23, which converts the flow into a number of separate, upwardly-moving streams, and then undergoes another abrupt change of direction and moves downward in the part of the passage between the innermost and middle conduits 15 and 16 respectively. During movement of the liquid through the separator the oil separates from the water and col- ,lects at the top of the container. The abrupt changes of direction, especially from upward to downward movement, assist the separation. The resulting separated water passes upward through the innermost conduit 15 out of the container through outlet 18, while the oil can be removed through an outlet 30 provided in the container ceiling.

' A discharge valve 31 fitted in thewater outlet 18 is arranged to prevent entry of liquid or air into the container through the outlet port, and is biased by a spring 32 to oppose flow of liquid'from the container interior, with the result that the liquid pressure throughout the container interior is increased.

A discharge valve 33 fitted in the oil outlet 30 is actuated by a liquid-operated motor, the valve being of the poppet type and the motor comprising a double-acting piston 34 working in a cylinder 35 and connected directly to the stem 36 of the poppet valve. A compression spring 37 is mounted around the stem of the poppet valve, but does not apply any biasing force to the valve while the valve is closed. The function of the spring 37 is described in detail below. When the poppet valve is closedthe liquid under pressure in the container interior is in contact with surf-aces of the valve such that the a liquid pressure biases the valve to maintain it'inthe such that the said sufficient pressure is lower than the 1;

minimum pressure which can be maintained in the container interior under normal operating conditions.

The liquid under pressure for operating the motor can comprise the separated oil or the separated water, and preferably as illustrated in this embodiment, the separated water is used since it is less likely to contain sticky impurities that woud clog the motor. The water is fed via a pilot slide valve 38, which is movable at will by an operator into any one of three positions. In such case the water may be fed to a valve shown diagrammatically and comprising a sliding control element with two spaced lands cooperating with ports at the ends of three pipes 39, 40 and 41.

In one position of the sliding element somewhat above that shown, the port of pipe 40 is uncovered by the upper land and the port of pipe 41 is masked by the lower land so that water can pass from the outlet 15 via pipe 39 and the valve and pipe 40 to the upper side of the piston 34 of the valve motor 34, 35, to move the oil discharge valve 33 to open the oil outlet 30. In another position of the sliding control element somewhat lower than that shown in the drawing the port of pipe 39 is masked by the upper land of the control element so that no water can flow through the valve to the valve motor 34, and the closing bias on the poppet valve 33 is able to close the oil outlet aperture 30. In a third position of the sliding control element (that shown in the drawing), the port of pipe is masked by the upper land and water is fed from water outlet 18 by way of pipes and ports 39 and 41 to the underside of the piston 34 of motor 34, 35 to effect very rapid movement of the valve 33 to the oil outlet 30.

In operation, when the oil discharge valve is opened the liquid pressure within the cylinder falls and it is necessary to ensure that it does not fall to a value which is too low to operate the motor. This is done by suitable choice of the compression spring 37 mounted around the stem of the poppet valve. When the valve is closed the spring is floating and applies no force to the valve. When the valve has opened a short distance and the biasing force provided by the liquid under pressure has decreased, the spring begins to act and further opening of the valve takes place against the action thereof, until the closing force of the liquid and spring equals the opening force of the motor. As the liquid pressure in the container interior falls the valve opening force provided by the motor decreases and the spring moves the valve toward the closed condition. As the valve closes the throttling of the liquid passing through it increases, the increased throttling maintaining the liquid pressure within the separator to a value above the said required a cocks also discharging through a sight-glass 44 into the drain. A pressure gauge (not shown) may be provided connected to the said inner conduit to enable the operator to ascertain whether the pressure therein is sufficient to operate the motor of the oil discharge valve. If at any time direct hand operation of the oil discharge valve is required this is done by means of an actuating lever 45 engaging the stem 36 of the poppet valve.

The separator need not be operated by hand and a control mechanism for automatic operation of the separator is illustrated in the drawing. The electric oil level indicators46 and 47, e.g., of the capacitance type,

are mounted in respective ports in the separator wall and are connected by leads 49 and 50 respectively to a controller 51, which controls the operating current supplied to a solenoid 52. The plunger 53 of the solenoid is connected mechanically to the slide of the pilot valve 38. The controller is arranged to respond to the indications given by the oil level indicators to operate the solenoid 52, and thus to operate the slide valve 38, to maintain the oil/water interface between the ports 46 and 47.

A third electric oil level indicator 48 is mounted in a respective port and is connected by leads 54 to a warning controller 55. If by failure of some part of the separator, e.g. failure of the oil discharge valve 33 to open, the oil/ water interface reaches the indicator 48 the controller 55 operates to give a warning to an operator and/or, for example, operates to stop the pump supplying liquid to the separator.

A separator in accordance with the present invention does not require a separate source of power for operation of the discharge valves the power being in elfect derived from the pump which feeds the liquids to be separated to the separator; The presence of the said biased valve 31 in the water outlet 18 assists in ensuring that the liquid supplied to the liquid motor for the valve 33 is under suflicient pressure to give rapid and effective operation of the motor. The said biased valve 31 also confers other advantages, for example, the time taken to discharge air that has collected in the chamber through the valve 29 is considerably reduced owing tothe increased internal pressure, and the danger is removed that the separator may empty itself completely by siphoning through the water discharge. Emptying of the separator in such a manner is very undesirable since any oil in the separator is drawn through the innermost conduit 15 and the water outlet 18, causing contamination thereof which is difficult to remove.

Instead of the biased valve 31 being fitted in the water outlet it may be fitted in the oil outlet, the motor-actuated valve being fitted in the water outlet.

In a particular example of a separator for oil and water of capacity 10 tons of liquid per hour, the container is 3 /2 feet'in diameter and 6% feet in height and the pressure normally required to cause flow of the liquid through the separator is about 15 p.s.i. The oil and water discharge ports are both 2 inches in diameter and the biased valve fitted in the water outlet only permits water to flow out of the container when the water applies a pressure of 15 p.s.i. to the valve, so that the pressure normally required to cause flow of liquid through the separator in accordance with the invention is at least 15 p.s.i.

I claim:

1. Apparatus for separating liquids of different specific gravities and for discharging the respective separated liquids automatically from the apparatus to maintain between predetermined levels within the apparatus an interface between the separated liquids, the apparatus comprising a closed container, an inlet to the container interior for liquids to be separated, two outlets from the container interior each for a different separated liquid constituent of the liquids to be separated, means within the container for separating the two constituent liquids, a throttling valve in one of the said two outlets opposing the discharge of the respective separated constituent liquid and thereby maintaining the liquid inside the container at an elevated pressure, a motorized valve in the other of the said two outlets, a fluid-operated motor coupled to the motorized valve for actuation thereof by operation of the motor, means operatively associated'with. said motorized valve for creating an increasing bias on said valve in the valve closing direction as said motorized valve opens, two stationary capacitative detectors for detecting the position of the said interfacqrelative to each detector, means mounting the said two detectors within the container and spaced vertically from one another to establish within the container the said two predetermined levels, and fluid-supplying means connected between the fluid-operated motor and the container interior and responsive to the said two detectors for supplying to the motor operating fluid for actuation of the motorized valve to maintain the said interface between the said two predetermined levels.

2. Apparatus as claimed in claim 1, wherein the said fluid-supplying means includes a pilot slide-valve con trolling the fluid supplied to said motor.

3. Apparatus as claimed in claim 2, wherein the said fluid-supplying means includes a solenoid having a plunger coupled to the said pilot slide-valve for operation of the latter in response to the said two detectors.

4. Apparatus for separating liquids of different specific gravities and for discharging the respective separated liquids automatically from the apparatus to maintain between predetermined levels within the apparatus an interface between the separated liquids, the apparatus comprising a closed container, an inlet to the container interior for liquids to be separated, two outlets from the container interior each for a different separated liquid constituent of the liquids to be separated, means within the container for separating the two constituent liquids, a throttling valve in one of the said two outlets opposing the discharge of the respective separated constituent liquid and thereby maintaining the liquid inside the container at an elevated pressure, a motorized valve in the other of the said two outlets, a fluid-operated motor coupled to the motorized valve for actuation thereof by operation of the motor, means operatively associated with said motorized valve for creating an increased bias on said valve in the valve-closing direction as said motorized valve opens, a stationary capacitative detector for detecting changes in the position of the said interface with respect to the level of the detector, means mounting the said detector within the container at a level between the said two predetermined levels, and fluid-supplying means connected between the fluid-operated motor and the container interior and responsive to the detector for supplying to the motor operating fluid for actuation of the motorized valve to maintain the said interface between the said two predetermined levels.

5. Apparatus as claimed in claim 4, wherein the said fluid supplying means includes a pilot slide-valve controlling the fluid supplied to said motor.

6. Apparatus as claimed in claim 5, wherein the said fluid-supplying means includes a solenoid having a plunger coupled to the said pilot slide-valve for operation of the latter in response to the detector.

7. Apparatus as claimed in claim 1 wherein the motorized valve in the closed position is biased towards the closed position by pressure in the container interior and said means for creating an increasing bias in said motorized valve in the valve-closing direction as said motorized valve opens, is rendered ineffective as said valve is closed.

8. Apparatus as claimed in claim 4 wherein the motorized valve in the closed position is biased towards the closed position by pressure in the container interior and said means for creating an increasing bias in said motorized valve in the valve-closing direction as said motorized valve opens, is rendered ineffective as said valve is closed.

References Cited in the file of this patent UNITED STATES PATENTS 1,516,132 Allen Nov. 18, 1924 1,921,689 1 Meurk Aug. 8, 1933 2,245,551 Adams June 17, 1941 2,342,950 Lovelady Feb. 29, 1944 2,361,577 Unthank Oct. 31, 1944 2,693,880 Schoenfeld Nov. 9, 1954 

